This paper, based especially upon the material in the Leyden Museum, may be regarded as a little attempt to show how much a revision of the Pycnonotidae is needed. A fundamental revision only, embracing the whole group, will be able to thoroughly differentiate the many genera, and it will be a thankful task, for instance, to thoroughly separate Xenocichla from Criniger ¹) and Pycnonotus. This latter genus is very unsatisfactorily defined, and undoubtedly contains too many heterogenous elements, which ought to be just as well excluded as are Otocompsa and Kelaartia. In fact the genus Pycnonotus should be restricted to the African and Syrio-Arabian species, which are sufficiently characterized by their plain earthy brown or sandy brown color, without white upper tail-coverts, without whitetipped tail and without any olive-green on the quills ²). The Asiatic forms with paler edgings to the feathers on the mantle, with white or ashy white upper tail-coverts and white tips to the tail-feathers, combined with the absolute want of any olive-green in their plumage should form a separate group with the generic name Molpastes Hume.